You’re right that no one can really pinpoint why they got into a particular school and someone else with similar qualifications didn’t. It is a matter of conjecture, regardless of what we read from so many kids here.
But something must have made the difference. And as long as the schools continue to ask for essays, I wouldn’t be willing to put anything less than my best foot forward in that area. It’s the single piece of the puzzle that speaks to you as in individual, as opposed to a series of statistics.
At the end of the day, no one really knows how much weight a particular adcom may choose to give to a good-- or a horrible-- essay. I would imagine they’re afforded a certain amount of leeway.
I think that strong stats- SAT/ACT/GPA- are more heavily weighted in general, because colleges want to know if you are a strong student, and will be able to do well academically, while at their college. The essays just add another dimension to the applications, and raise the bar. So, they’re looking at your personality, and looking for other aspects of you that they may not have considered, such as extraneous circumstances, or a unique upbringing. Something that would help admissions officers to build a “diverse” class. (I put diverse in quotations because that’s the ideal goal for colleges, but it isn’t always met.) Definitely make sure your academic stats are very strong, and then with your essays, go a little wild. Tell them something they can’t learn from looking at your basic reported information. As for the weight of the essays, every college will take them into consideration differently. I think that state schools might not use them as make or break-ers, but will definitely rely on them to single out applicants that are stronger than others, or provide a sort of context for said applicant’s scores. For example, a student attaining an unweighted 4.0 GPA with all APs, while working two jobs to help their family, would be given a lot more recognition. In addition, essays could explain to officers why an applicant couldn’t make a 4.0, and even buffer out the rest of your application. Essays can’t hurt you, unless you include information that will make you look bad, or add no value to your application. Essays are really a supplement, meaning that they’re not typically a decisive factor, but can definitely tip the scales. I hope this ramble makes sense…
The more selective the school, the more important your essays become in differentiating you from the other couple applicants who on paper appear to be very similar to you.
Dad has two friends who are admissions counselors at Stanford and UCLA. The one from Stanford was formally with Harvard. Both have stated unequivocally that the essay is very important. In addition to the many reasons given by earlier posters, the essay is also important because, quite simply, they expect a strong candidate to write a strong essay. In their mind, it raises a red flag when a candidate with strong grades and scores submits a subpar essay; it’s too incongruous to be overlooked. Conversely, a strong essay from a candidate with less than stellar grades and scores could warrant further review and consideration. Hope that helps.
In my opinion, the essay is a critical component of the application. Without the essays, admissions only see numbers, numbers that will be very similar on almost all applications submitted.
OP mentioned the essay being read in 3-4 minutes then checked off or not. I think most review processes have several readers of your application at different phases of your application. A lot of colleges discuss 3 phases.